In general, in a conventional display device with front light sources (also referred to as front-lit display), a light guide can be integrated into such a device and optically coupled to one or more of the front light sources. Light emitted by the one or more front light sources can be injected into the light guide via one or more optical modes of the light guide, and such injected light may be referred to as in-coupled light. In addition, in-coupled light can be scattered off by a grating pattern or other scattering patterns, such as scattering centers, that can be integrated into the front-lit display; such scattered off light can be referred to as out-coupled light. Yet, a significant portion of light in-coupled into the light guide may not emanate as out-coupled light through such grating patterns or scattering centers. Light that is not out-coupled by the grating patterns or scattering centers may escape the free edges of the light guide and reduce efficiency in the optical design of the display.
In addition, typical front-lit displays may present significant color non-uniformity that may be readily perceivable to the human eye. Several likely mechanisms may contribute to such color non-uniformity, including light scattering, light absorption, light refraction, light interference, and/or light diffraction. With respect to light absorption, in a typical front-lit display, the progressive absorption of a certain wavelengths along the length of the display device can contribute to color non-uniformity, as such absorption may lead to progressive spectral shaping of a resulting optical emission spectra that it is perceived as color by an end-user of the display device.